1. Field of the Invention
The invention generally relates to an optical apparatus, and more particularly, to an optical engine module with heat-dissipating effect.
2. Description of Related Art
Digital light processing (DLP) projection apparatus works based on using an illumination beam emitted from a light source, after being filtered and converted into red, green and blue three color lights (R, G, B) by a color wheel in high-speed rotating, to be transmitted onto a digital micro-mirror device (DMD) to get an imaging beam by converting, followed by projecting the imaging beam onto a screen to form frames with a projection lens. The DMD continuously change the angles thereof, in association with a high-speed rotating color wheel and taking advantage of the human eye's vision persistence effect, a pixel gives out different color variations. In addition, a laser light source could be used to emit a blue light beam, and after the blue light beam excites the phosphor on a phosphor wheel, a red beam and a green beam could be produced as well for getting the imaging beam.
To avoid external dust from depositing on the color wheel to affect the projection quality of the projection apparatus or cause the projection apparatus abnormal working, the color wheel is disposed in an enclosed space formed by a casing in some designs so as to isolate the external dust. However, the heat produced during running the motor of the color wheel is hard to be discharged from the enclosed space, while the light beam with high energy may lead an over heat of the phosphor powder on the color wheel to affect the optical converting efficiency.
US Patent publication No. 2012013854 discloses a dustproof structure of an optical assembly, where a fan is used to produce an airflow for cooling the color wheel, the motor and the optical channel. U.S. Pat. No. 6,755,554 discloses a color wheel structure, wherein the cover body and the body of the color wheel have cooling fins, and the fins could be heat-dissipated by a cooling fan. China Patent Application No. 2015621140 discloses a projector, where a casing encloses a color wheel, and the casing has a light-passing hole and a transparent substrate to enclose the light-passing hole. U.S. Pat. No. 7,926,953 discloses a projection apparatus, wherein the projection apparatus has a sealed optical assembly, and a cooling apparatus is employed to absorb the heat in the sealed space and discharge the heat out of the sealed space.